Defective chloride transport in epithelial cells results from mutations in the cystic fibrosis transport regulator (CFTR). A potential therapeutic approach for treatment of cystic fibrosis (CF) would be to restore chloride transport to airway epithelial cells. In this pursuit, a series of water-soluble chloride-conducting peptide capable of spontaneous insertion into epithelial cell membranes have been synthesized. This family of peptides is modeled after the pore-forming amphipathic helical transmembrane sequence of the brain glycine receptor. (M2GlyR). The M2GlyR peptides have been evaluated for their ability to increase chloride and water transport across epithelial cells in monolayers. The exciting results from these preliminary studies suggest that this class of peptides may be capable of restoring normal function to CF airway epithelial cells. The proposed research will involve electrophysiological and biophysical characterization of the M2GlyR peptide family as well as molecular modeling studies to allow for further evaluation of these compounds as therapeutics agents in the treatment of CF lung disease. Evaluations of the effects of M2GlyR peptides on whole-cell currents will be done against the background endogenous currents of epithelial cell lines. Single channel analysis of the M2GlyR peptides will be done with the planar lipid bilayer technique with the emphasis on evaluating ionic selectivity. Peptide-lipid interactions will be assessed by a variety of biophysical techniques. Molecular modeling will be used to define the relationships between structure and function for the M2GlyR family of peptides.